Application of Rank Annihilation Factor Analysis to the Spectrophotometric Determination of the Formation Constants of Complexes of a New Schiff Base and Some Transition Metals in Different Media

The complex formation between a new synthesized Schiff base and the cations Ni(2+), Co(2+), Cu(2+), and Zn(2+) in ethanol, dimethylformamide (DMF), and acetonitrile (AN) was studied spectrophotometrically using rank annihilation factor analysis (RAFA). According to molar ratio data and Job's plots, the stoichiometry of complexation between the Schiff base and the cations Co(2+), Ni(2+), and Zn(2+) was 1:2, and that between the Schiff base and Cu(2+) in all solvents and Zn(2+) in AN was 1:1. Formation constants of these complexes were derived using RAFA on spectrophotometric data. In this process the contribution of the ligand is removed from the absorbance data matrix when the complex stability constant acts as an optimizing object, and simply combined with the pure spectrum of ligand, the rank of the original data matrix can be reduced by one by annihilating the information of the ligand from the original data matrix. Also the effect of surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and Triton X-100 on the complex formation constant of Cu(2+) with the Schiff base in DMF was investigated.